1. Field of the Invention
The present invention relates to an apparatus installed non-intrusively and directly to a process stream for measuring fluid viscosity and density.
2. Description of the Prior Art
A need exists for effective instrumentation and diagnostic technology for coal combustion, pyrolysis, and cleanup processes. Control instruments are needed for monitoring specific process parameters such as, viscosity, temperature and flow rate. An on-line viscometer can be used for real-time coal-slurry process control, for example, in the control of slurry viscosity at the slurry atomization step of a combustion process. Furthermore, accurate measurement of slurry viscosity can also ensure efficient and safe operation of other process equipment, such as pumps, valves and nozzles.
Rheological properties of a coal slurry determine most engineering design requirements of a coal process in which a slurry is used. For example, the flow pattern of a coal-slurry in a pipe is related to the shear viscosity of the slurry or to the flow consistency number and flow behavior index when the slurry behaves as a non-Newtonian fluid. A dilute coal/water slurry that is less than 15% by weight can be considered a Newtonian fluid, but higher concentration slurries display non-Newtonian behavior. The apparent viscosity of such a non-Newtonian slurry is dependent on shear rate. In a coal combustion process, the coal slurry is typically under high shear rate at the injection nozzle of the slurry atomizer. There is increasing evidence that the size of the slurry drops at the exit of the atomizer strongly depends on slurry viscosity or rheological properties. It would therefore be of great value to the control of atomization if slurry viscosity could be measured at the atomizer.
It is an object of the present invention to provide an improved method and apparatus for measuring fluid or liquid viscosity.
It is an object of the present invention to provide an improved method and ultrasonic viscometer for measuring liquid viscosity.